The key difference between genetic disorders and polygenic diseases is that genetic disorders are caused by chromosomal mutation, a combination of gene mutations, or a single gene mutation, while polygenic diseases are only caused by a combination of gene mutations.
Genetic disorders and polygenic diseases both occur due to mutations in genetic material. Genetic disorders occur when a mutation affects the genes or when people have the wrong amount of genetic material. Genetic disorders can be chromosomal (having missing or duplicated chromosome materials), multifactorial, polygenic (stem from a combination of gene mutations), single gene, or monogenic (occurs from a single gene mutation).
CONTENTS
1. Overview and Key Difference
2. What are Genetic Disorders
3. What are Polygenic Diseases
4. Similarities – Genetic Disorders and Polygenic Diseases
5. Genetic Disorders vs Polygenic Diseases in Tabular Form
6. Summary – Genetic Disorders vs Polygenic Diseases
What are Genetic Disorders?
Genetic disorders occur when a mutation affects the genes or when people have the wrong amount of genetic material. They are caused by chromosomal mutation, a combination of gene mutations, or a single gene mutation. There are many types of genetic disorders, including chromosomal disorders (Down syndrome, fragile X chromosome syndrome, Klinefelter syndrome, Turner syndrome, trisomy 18, and trisomy 13), polygenic disorders (late-onset Alzheimer’s disorder, arthritis, autism, cancer, coronary artery disease, diabetes, migraines, and spina bifida), monogenic disorders (cystic fibrosis, deafness, Duchenne muscular dystrophy, familial hypercholesterolemia, hemochromatosis, neurofibromatosis, sickle cell anemia, and Tay Sachs disease).
The common symptoms of genetic disorders include behavioural changes, breathing problems, cognitive deficits, eating and digestive issues, limb or facial anomalies, movement disorders, neurological issues, poor growth or short stature, and vision and hearing loss. The risk factors for genetic disorders include chemical exposure, radiation exposure, smoking, and UV exposure to the sun.
Figure 01: Genetic Disorders
Genetic disorders may be diagnosed through DNA testing, blood testing, and amniocentesis. Furthermore, treatment options for genetic disorders include chemotherapy, dietary supplements, physical, occupational, or speech therapy, blood transfusion, surgery to repair abnormal structures, special treatment like radiation therapy, and organ transplant.
What are Polygenic Diseases?
Polygenic diseases are genetic diseases only caused by a combination of gene mutations. They are also called multifactorial or complex diseases. Polygenic diseases like heart disease, arthritis, type 2 diabetes, and neurodegenerative diseases are caused by mutations in several genes. The cumulative effect of gene mutations results in polygenic diseases. Other risk factors for polygenic diseases include age, sex, nutrition, etc. The common symptoms of polygenic diseases include excessive urination, persistent thirst, abnormally high glucose levels in the blood, polyphagia, polydipsia, cognitive problem, and growth problems.
Polygenic diseases can be diagnosed through modern genomic techniques like genome-wide association studies (GWAS). Furthermore, polygenic diseases can be treated through modern gene therapy and CRISPR-based editing of multiple genes.
What are the Similarities Between Genetic Disorders and Polygenic Diseases?
- Genetic disorders and polygenic diseases are both due to mutations in genetic material.
- Both are related to each other.
- They may follow non-Mendelian inheritance.
- Both may show similar symptoms, such as cognitive defects and growth problems.
- They can be diagnosed through genetic testing.
- They are treated through surgeries and gene therapies.
What is the Difference Between Genetic Disorders and Polygenic Diseases?
Genetic disorders are caused by chromosomal mutation, a combination of gene mutations, or a single gene mutation, while polygenic diseases are only caused by a combination of gene mutations. Thus, this is the key difference between genetic disorders and polygenic diseases. Furthermore, genetic disorders follow Mendelian or non-Mendelian inheritance, while polygenic diseases always follow non-Mendelian inheritance.
The below infographic presents the differences between genetic disorders and polygenic diseases in tabular form for side-by-side comparison.
Summary – Genetic Disorders vs Polygenic Diseases
Genetic disorders and polygenic diseases are both due to mutations in the genetic material. They are related to each other. Genetic disorders are caused by chromosomal mutation, a combination of gene mutations, or a single gene mutation, while polygenic diseases are only caused by a combination of gene mutations. So, this is the key difference between genetic disorders and polygenic diseases.
Reference:
1. “Genetic Disorders: What Are They, Types, Symptoms & Causes.” Cleveland Clinic.
2. Lvovs, D, et al. “A Polygenic Approach to the Study of Polygenic Diseases.” Acta Naturae, U.S. National Library of Medicine.
Image Courtesy:
1. “Human chromosome diseases set en” By Ігор Пєтков – Own work (CC0) via Commons Wikimedia